(a) Field of the Invention
The present invention relates to a board transmitting device for an upright PC board etching machine.
(b) Description of the Prior Art
At present, the etching machines used in manufacturing PC boards include PC board translational etching and upright PC board etching. In the former type, spraying of corrosive agents includes upward and downward spraying. The latter is usually applied to larger circuits (e.g., PC boards for radios), in which the corrosive agent is ejected from a nozzle and is sprayed downwardly to a PC board placed horizontally on a conveyer to perform etching of circuits. Although the construction is simple, there is a drawback that during etching, the liquid on the horizontally placed PC board cannot be easily removed. The liquid will form a water film to slow down the subsequent etching washing force applied so that the etching effect is affected. A greater washing force is required in order to allow the corrosive agent to flow along the board surface. The quality of a PC board thus formed is not satisfactory.
The spraying of corrosive agent upwardly is generally used on etching finer circuits on single-sides PC boards. The corrosive agent is ejected from a nozzle and is sprayed upwardly onto a PC board placed horizontally on an open type conveyer to perform circuit etching. Due to the weight of the liquid, there is no accumulation of liquid on the board. The etching effect is therefore better. However, the construction is complicated and costly.
With greater demands for more double-sided PC boards, manufacturers have to use double-sided etching techniques. Earlier, translational etching was adopted. With translational etching, the corrosive spraying mechanism is disposed at the upper end, while the corrosive agent upward spraying mechanism is disposed at the lower end to thereby achieve a double-sided etching effect. However, this construction also suffers from the drawback associated with translational single-sided etching. The product quality is also not satisfactory.
To overcome the aforesaid drawbacks, there have been developed a type of etching machine for performing upright PC board etching. The PC board is clamped and transferred in an upright manner, and the corrosive agent is sprayed thereonto from the outer ends of two side plates so that etching can be done on both sides of the board. There is not the problem of water accumulated on the board or the drawbacks associated with upward spraying of corrosive agent. However, the PC board transmitting mechanism in this construction is not satisfactory, as described hereinafter.
FIG. 1 is a schematic view of a vertical clamping suspending type transmitting mechanism. A plurality of clamps 20, 21 . . . are suitably spaced apart and secured on a moving rail 10 to clamp PC boards 30 in advancement. Spraying nozzles at outer ends of two side plates spray a corrosive agent thereonto to perform circuit etching. Since the lower end of the PC board 30 is suspended, it will shake when subjected to the pressure of the ejected corrosive agent, and the downward clamping force of the clamps 20, 21 . . . will decrease gradually. Oftentimes, the clamps 20, 21 . . . cannot clamp the PC board 300 tightly to allow it to drop. The etching effect is therefore not good, and the etching operation is affected.
Referring to FIG. 2, which shows a vertical type transmitting mechanism of an etching machine. A PC board 40 is erected on a conveyor 50, and a plurality of fine wires 60, 61 . . . are provided on both sides of the PC board 40 to prevent the PC board 40 from shaking. These fine wires 60, 61 cannot be too close to the PC board lest that the PC board 40 is clamped too tightly by these wires 60, 61 to hinder advancement of the PC board 40 on the conveyor 50. Due to the barrier effect of the loose wires 60, 61 . . . during the spraying of corrosive agent onto the PC board 40, the PC board 40 will shake, which affects the etching effect. In addition, the PC board 40 is simply placed on the conveyor 50 and is not positively retained in position. As such, the PC board 40 may be caused to displace by the force of spraying when passing through the corrosive agent spraying mechanism on both sides thereof so that the PC boards 40 advance at an irregular speed, which considerably affect the etching effect.
The present invention relates to a board transmitting device for an upright PC board etching machine.
The primary object of this invention is to provide a board transmitting device for a Upright PC board etching machine, which includes a plurality of serial wheel frames with rotary wheels mounted thereon to clamp and advance PC boards so that the PC boards can advance at a regular speed and stably.
Another object of this invention is to provide a board transmitting device for a Upright PC board etching machine, in which the components are inter-engageable to facilitate replacement and maintenance thereof and to enhance etching efficiency.
The foregoing objects and summary provide only a brief introduction to the present invention. To fully appreciate these and other objects of the present invention as well as the invention itself, all of which will become apparent to those skilled in the art, the following detailed description of the invention and the claims should be read in conjunction with the accompanying drawings. Throughout the specification and drawings identical reference numerals refer to identical or similar parts. Many other advantages and features of the present invention will become manifest to those versed in the art upon making reference to the detailed description and the accompanying sheets of drawings in which a preferred structural embodiment incorporating the principles of the present invention is shown by way of illustrative example.